It has long been recognized in the art that contact lenses must remain free of surface deposits in order to maintain their wearing comfort and optimum vision and reduce the potential for ocular change. Unfortunately, contact lenses are susceptible to acquiring surface deposits from exogenous sources (mascara, hair spray, etc.) and endogenous sources (mucous, oily meibomian secretions, etc.). Silicone containing contact lenses are the most vulnerable of all contact lenses to the acquisition of tenacious, waxy surface deposits that are difficult, if not impossible, to totally remove without damaging the lens.
Previous hard and soft contact lens cleaning solutions have used a variety of water soluble cleansing agents, in addition to water soluble hydrating polymers in sterile homogeneous aqueous solution. Other cleaning agents have employed thixotropic synthetic water soluble polymers and thixotropic synthetic clays with detergents to give stiff gels for the cleaning of hard contact lenses. The cleaning process involves removal of contaminants from the surfaces of the contact lens without scratching or otherwise affecting the lens material.
Abrasives are employed in the manufacturing of contact lenses in a polishing process which provides the contact lens with optical quality surfaces. Polishes are also employed to blend the edge of the lens and to make minor alterations in the power of the lens. Abrasive materials have not been used in contact lens cleaning solutions heretofore, perhaps because such abrasives would have the propensity to scratch or otherwise alter the surface of the plastic contact lens, thus leading to a reduction in optical clarity as well as enhanced eye irritation.